Furnace for ore-roasting



E. BRACQ.

FURNACE FOR ORE ROASTING.

APPLICATION man MAY 8. I914.

Patented Oct. 26, 1920.

4 SHEETS-SHEET I.

E. BRACQ. FURNACE run one mmsrme.

' APPLICATION FILED MAY 8, 1914. I 1 35 49 Patented Oct. 26, 1920.

E. BRACQ. FURNACE FOR ORE ROAST'NG.

APPLICATXON FILED MAY 8, 1914.

Patented Oct. 26,1920.

4 SHEETSSHEET 3.

E. BRACQ.

FURNACE FOR ORE ROASTING.

APPLICATION nuzb MAY 8, I914.

1,356,849. 4 Patented Oct. 26, 1920.

4 SHEETS-SHEET 4- T ig, 19.

UNITED STATES EMILE BRACQ, OF PAS DE CALAIS, FRANCE.

FURNACE FOR ORE-ROASTING.

Specification of Letters Patent.

Patented Oct. 26, 1920.

Application filed May 8, 1914. Serial No. 837,182.

I '0 all whom it may concern:

Be it known that I, EMiLE BRAGQ, a citizen of the French Republic, residing at Pas de Calais, France, have invented certain new and useful Improvements in Furnaces for Ore-Roasting, of which the following is a specification.

This invention relates to ore-roasting furnaces having means for stirring and moving the ore comprising one or more stirring arms which perform a movement following the surface of a helical hearth, or, a series of superposed circular hearths, and at the same time aremoved through a closed path of substantially rectangular form, so as to separate narrow slices or layers of ore and move these layers singly a short distance along the hearth.

According to this invention the arms and the member supporting the same are situated inside the furnace and are water cooled, while the mechanism for giving the arms their various motions are located entirely outside the furnace.

In the accompanying drawings two constructions of furnace embodying the improvements are shown, in which Figure 1 is a sectional elevation of a furnace with a helical hearth;

Fig. 2 is a detail view, partly in elevation and partly in section of a portion of the mechanism for moving the arms, on an enlarged scale;

Fig. 3 is an enlarged vertical section of the driving device;

Fig. 4 is a horizontal section of same on line EF, Fig. 3;

Fig. 5 is another vertical section perpendicular to F igQ3;

Fig. 6 is a horizontal section on line A-B, Fig. 3; 7 Fig. 7 is a horizontal section on line C-D,- Fig. .3;

Fig.- 8 is a vertical section on line G-H, Fig. 6;

Fig. 9 is a detail sectional view showing the mechanism which controls the angular movement of the arms carrying the stirring blades;

Fig. 10 is a vertical section of a modification of the device applied to a furnace. comprising several non-helical floors arranged one above the other.

The central spindle 1 is cooled by a circu-' lation of water enteringby an inlet-pipe 2 and escaping through overflow pipes 3. The spindle 1 is provided with a hollow arm or arms 4 and 5 in which there is also circulation of the cooling water.

The tubular arms, of which there may be any number, support scraping and stirring blades 7 and 8 of suitable shape, easily interchangeable, which are maintained at a low temperature by contact with the watercooled tubular body of the arms.

The spindle l secured to the actuating mechanism is given by the latter all the movements for effecting the separation of the ore into slices, said movements including the moving of the ore along the hearth, the stirring of the ore, and the scraping of the hearth.

The movements which it is desired to 010- I tain are set out more in detail as follows 1. A progressive axial and rotary movement of the arm-supporting spindle for the purpose of giving the arms a helical movement corresponding to the pitch of the helical hearth.

2. Vertical and horizontal movements combined with the preceding movement and enabling the arm or arms to be brought down on the layer being roasted, to penetrate into the same and to separate a slice may vary so as to'increase the height. of the hearth at each revolution if desired, either to increase the space allotted to the escape of the gases, for reasons of temperature, or for any other reason. In these cases it is necessary to provide the screw 10 with a pitch corresponding to the axial spacing of the various floors of the hearth.

The screw 10 is connected at its upper end to a pivoted rod 11 connected by a univer sal joint to a balance beam l2 provided at the end with a balance weight 13, whereby thescrewlO, the vertical hollow spindle 1 and the hollow arm or arms 4 and 5 con nected thereto, are suspended and balanced.

The combined movements of gradual rotation and elevation of the arm-holding spindle 1, and of alternate rising and falling associated with an oscillating movement, are obtained as follows A driving shaft 14, arranged at the top of the furnace, is provided with fast and loose pulleys 16 by which the shaft is driven during the working period of the arms on the hearth, and has another set of fast and loose pulleys 15 thereon, which pulleys 15 are smaller in diameter than the pulleys 16. The pulleys l5 drive the shaft during the period when the arms descend upon the hearth without stirring the material, giving the shaft a greater speed during said period.

The shaft is further provided with a bevel pinion 17 and a clutch l8 controlled by levers 19 which levers are operated at the proper time by a stop 10 arranged on the screw 10 at the desired place and acting on the point 20 of the levers 19. The bevel I pinion 17 is in mesh with a second pinion 21 driving with it a spur wheel 22.- The latter transmits the movement to a spur wheel 23, which is keyed to a vertical crank shaft 24. Around the spindle 10 is a column 32 surrounding which is the collar 26, Figs. 3 and 7, which allows the spindle 10 to slide vertically. The collar 26 has two fixed keys 45 which engage grooves 31 in the screw 10,- passing through slots 46 in the column 32. The collar 26 has extending therefrom two arms 29, between which travels a slide block 30 driven by the crank-shaft 24, thus producing an oscillating angular movement of the collar 26. It will therefore be seen, that when the crank-shaft 24 rotates, it imparts an angular oscillation to the screw 10. To the base of the column 32 is secured a toothed driving ring 34 driven by a pinion 35 rotated by a spindle 36, a wheel 37, and a pinion 38 secured to the driving-shaft, so that the column-32 rotates on its support 33.

A nut 27 (Figs. 2 to 5) engages the helical grooves 31 of the spindle 10 and carries a rotary collar 28 connected by means of two trunnions 43 and links 28,'to bell crank levers 25 which are rocked to and fro by the crank-shaft 24. When the said crankshaft 24 rotates,besides giving the screwed spindle 10 the oscillating movement above described, it also imparts by means of the levers 25 an alternate rising and descending movement to the screw 10 This is effected by a cross-head 42 on the crank-pin of the crank-shaft 24, which cross-head pushes to and fro a guide 41 to which is jointed connecting rods 40 the other ends of which are jointed to the bell-cranks 25.

The nut 27 only rotates through part of a turn as the collars 39 (Figs. 2, 4 and 9)' engage a toothed portion on the nut 27 and can slide between the bearings 39 so as to limit the angular movement of the nut 27 The toothed portion is moreover of such a height that the nut is enabled to rise and descend to a certain extent (as shown in Fig. 9). Thus the nut which is caused to rise and descend by the levers 25 and 28, compels the screw 10 to rise and descend also.

The operation of said device is as follows:

The shaft 14 being set in motionand driven by the fast pulley 16 (the cross belt of the pair of fast and loose pulleys 15 hearing on the loose pulley) the shaft 36 is driven by means of the pinion 38 and chain wheel 37 and drives, in its turn, by means of the pinion 35, the spur-wheel 34 which is fast to the column 32. This column rotates and carries with it the crank shaft 24 and associated parts, so that by means of the keys 45 mounted upon the collar 26, the screw 10 rotates also, while owing to the nut 27 being stationary, the screw gradually rises, the keys 45 sliding in the grooves 31. The spindle 1 with the arms also turns the arms 4 and 5 traveling along and to the to of the helical hearth.

uring this movement of the screw, the clutch 18 causes the shaft 14 to engage the pinion 17 which drives the crank-shaft 24 by means of the pinion 21 and the spurwheels 22 and 23, and transmits by meansof the slide 41 and levers 25 and 28, a slight reciprocating vertical movement to the nut 27 and consequently to the screw 10 and the spindle 1 andarms 4 and 5, so that said arms alternately rise out of and descend into the material during their gradually advanclng movement,

To allow this up and down movement of the screw 10 to take place without resistance from the nut 27, the said nut can perform a slight angular movement owing to the action of the collars 39 engaging the teeth on the nut as aforesaid.

Besides the movements above described, the arms accomplish a separate movement forward and backward which allows them to carry away the slice which they have separated by entering into 'the material, and then to come back to separate a fresh slice.

This forward and backward movement is produced by the rotation-of the screw 10 around its axis under the action of the oscillation transmitted to the collar 26 bythe V crankshaft 24. Obviously, the time of these movements is controlled so that the carrying away of the material takes place when these levers and disengage the clutch 18, the

beltsof the pulleys sets 15 and 16 being moved at the same time upon their fast and loose pulleys, respectively. The shaft 14; is thus driven in the opposite direction at a greater speed but the crank-shaft does not rotate because the wheel 23 is no longer actuated, The screw 10 being carried along by the keys 4:5 in the movement of the column and the nut 27 being stationary, the screw accomplishes its downward course, the arms meanwhile being raised above the material and remaining in this position to the end of the stroke owing tothe crankshaft remaining stationary.

Fig. 10 gives an example of the application of these means for cutting and advancing the material, and scraping the hearth in a furnace with superposed floors.

In that case, the tubular screw 10 is done away with and the central spindle l is eX- tended, the nut 27 being also eliminated. The spindle is submitted to the other move ments described in connection with Fig. 1.

The clutch and the lever system 18 and 19 are no longer necessary, as the work can be carried out continuously.

What I claim as my invention and desire to secure by Letters Patent is 1. An ore-roasting furnace comprising an annular hearth, a vertical shaft centrally disposed therein, stirring and scraping arms secured to said shaft and extending across the hearth, mechanism for moving the arms in a path following the surface of the hearth, mechanism for moving the arms in vertical planes and in a closed path of small amplitude whereby the ore is separated into narrow slices and said slices moved forward successively over the hearth, the said two mechanisms being external to the furnace and capable of operating simultaneously, and means for cooling the arms and shaft.

2. An ore-roasting furnace comprising a helical hearth, a vertical shaft rotatably and slidably mounted therein, stirring and scraping arms secured to said shaft and extending across the hearth, mechanism for giving the shaft a progressive axial and rotary movement, whereby the arms move in a helical path following the surface of the hearth, mechanism for giving the shaft both axial and angular oscillations whereby the arms move in a closed path of sub-v stantially rectangular form, said two mechanisms being external to the furnace and capable of operating simultaneously, means for disabling. the oscillatory movements of the arms during the return travel of the arms, and means for cooling the arms and shaft.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EMILE BRAoo.

Witnesses:

ALFRED C. HARRISON, HENRI MIAT. 

